Actually that’s quite neat! On power transistors like that with high pressure fixings (e.g. screw & pressure plate) it’s supposed to squeeze out all round the sides.
The only time you should ensure that you use a small amount of compound (i.e. only just sufficient) is where the heat spreader area is smaller than the overall size of the device’s case and you are using low pressure fittings (this is the situation with computer CUPs & heatsinks). This is necessary as with low pressure fittings there isn’t enough force to squeeze out the excess and then you end up with too thick a layer of thermal paste (less thermally conductive than aluminium).
I think it’s a fair comment. If I had the allocated funds to be able to buy one it wouldn’t stop me from purchasing one. But I was a little bit embarrassed when my friend pointed it out with disappointment. It would be nice if they did do that I couldn’t see it being a large problem but hey I’m just a forum a member.
Not really, the most effective technique for high pressure interfaces (as in getting the best performance from the paste) is to apply a significant quantity to the underside of the device, fit the pressure plate, position the device and tighten to the prescribed torque allowing the paste to squeeze out of the sides. Any attempt at making it ‘neater’ results in poorer thermal performance.
I’d be more concerned with the transistor leg (or extension) to PCB soldering. The centre leg of fourth from left transistor looks like there is only a thin piece of solder connecting it to the PCB. (or maybe it’s an optical illusion)
The left leg of the third from left transistor looks a bit dodgy.
It really is messy stuff, trying to clean any excess can be a real headache & it ends up spread everywhere, albeit thinner. It leaves white marks on black anodising.
It’s fine. The soldering would of been done the other side of the board and then migrated through the hole to the side we can see. As long as the other side of the board is ok, then all is good. I take it that unit had the DR upgrade done afterwards? by the looks of things, i would’ve said it has. Unless Dunc has had his foot to the floor and red lining it at every turn.
There is so way of telling from the photo if the other side is OK.
The burnt PCB indicates an attempt was made to remove the old legs, but only a few where removed. So, the legs of the new regs where either soldered into the hole, or soldered onto the original legs which are still in situ.
If this was done without gaining access to the underside, (to save time) some of the legs are only soldered on the top of the board. Which, along with the solder spatter, doesn’t look very good.
Shortly after Lockdown began my iMac went Tonto and packed in. Watching a video on YouTube I was informed that it could be the Graphics card giving up the ghost. Only course of action was to take the computer apart and remove the Graphics Card and bake it in the oven for 10 minutes at 190C which I duly did. I ordered the thermal paste which arrived from Greece and took four days to arrive. Liberally applied to the relevant Processor and support chips and Transistors and hey pesto one functioning iMac.
It’s an IT wide issue. Anyone who works with computers, and in particular those who work in computer maintenance or build their own PCs will be every bit as familiar with the potential issues of the incorrect application of thermal paste as any Naim engineer.
I have built my own PCs (and those for members of my family) for as long as I can remember, and am aware that it is quite tricky to apply just the right amount of thermal paste between CPUs and cooling devices in order to achieve optimum heat dissipation. Too much thermal paste can be almost as potentially harmful as too little.
No picture of the offending surplus paste has been posted, but it should certainly not be over applied in a slap-happy manner as suggested by the OP.
That rule (just enough) only applies to low pressure device/heatsink interfaces (such as CPUs), for high pressure interfaces the best approach it to apply more than is needed and let it squeeze out.
What you have to bear in mind in the photo of my 500 the top grill has been removed, so the thermal paste is exposed. It formed such a tight bond with the top grill it took a little force to remove it. The act of lifting spread the paste up the side of the heat sink.
The paste is so tacking it takes some removing and and it gets everywhere if you try, so its best left.
When the top grill and wings are replaced as the other photo of the insides of a 500 the paste is not visible
More is best as I was informed
